Suction producing muffler



June 23, 1936; E. c. HORTON SUCTION PRODUCING MUFFLER Filed Sept. 5, 1933 R O T N. E- V m @M TTQRNEYS Patented June- 23, 1936 UNITED STATES SUCTION PBODUCIN G MUFFLER Erwin C. Horton, Hamburg, N. Y., assignor to Trlco Products Corporation, Buffalo, N. Y.

Application September 5. 1933. Serial No. 688,219

5Claims.

This invention relates to motor vehicles and internal combustion engines and particularly to an apparatus having the combined efiect of mufiling the exhaust from the vehicle, or internal combustion engine, and of providing a source of suction or less than atmospheric pressureforoperating pumps, horns, windshield cleaners, or other devices such as those which may be associated with the vehicle or engine.

In general the present invention contemplates, in apparatus wherein the flow of gases expelled from the engine through a muflling zone is caused to create a zone of sub-atmospheric pressure for the purposes indicated above orotherwise, the provision of means for eliminating excessive back pressures in the engine exhaust passage, such means including an automatic control mechanism adapted to function under the varying conditions of engine operation. For example, when the engine is operating at low speed or under light load, the contemplated means will be automatically adjusted to utilize the kinetic energy of a large portion of the flowing exhaust gases for the production and maintenance of the zone of sub-atmospheric pressure; and when the engine is operating at high speed or under great load and is exhausting relatively large quantities of gases, such as would tend to create excessive back pressure or pressure between the engine and the suction producing apparatus and also create an excessive degree of suction, the means contemplated will automatically efiect a by-passage of a considerable portion of the exhaust gases into the atmos phere, to thereby maintain the suction and back pressure at substantially constant degrees. The means for governing the automatic control are constructed and arranged in such manner as to be unaffected by the heat of the exhaust gases, which heat may vary in temperature and quantity in accordance with operating conditions of the engine, such as load, speed and other factors.

These and other objects and advantages, including those inherent in the various features of arrangement and formation of parts, will become apparent from the following description of the one typical embodiment of the invention that is illustrated in the accompanying drawing, wherein:

Fig. 1 is a longitudinal section apparatus;

Fig. 2 is a transverse section, being taken substantially along line 2-2 of Fig. 1;

Fig. 3 is a transverse section, being taken substantially along line 3-3 of Fig. 1; and

Figs. 4 and 5 are fragmentary longitudinal seethrough the tional views taken respectively through portions of the apparatus which appear in elevation in Fig. 1.

As shown in Fig. 1, the apparatus includes a casing comprising an elongated tubular member II, a closure member I2 for one end of member II and provided with a nipple I3 for attachment to a conduit I4 extending and connected to the engine exhaust passage or exhaust manifold, and a 010- sure member I5 for the opposite end of tubular member II. Closure member I5 has an opening I6 which may open directly into the atmosphere, or, as illustrated, may be provided with a nipple ll for connection to a conduit I8 leading to the atmosphere.

Extending transversely of and within tube II, in spaced relation to closure I2, and preferably secured to the walls of member II, is a wall I9 having opening 2i in substantial alignment with nipple I3, and having plural perforations 22 for passing fluid from the inlet opening (nipple I3) side of wall 59, designated inlet chamber 20, to the other side of the wall, designated chamber 23. Another transverse Wall, 24, spaced from closure I5 serves with the latter and member I I to form outlet chamber 25. Wall 24 has an opening 26 aligned with opening 2| in wall I9, and also has an opening 21 in substantial alignment with apertures 22 of wall I9.

A Venturi tube connects chambers 20 and 25, and comprises a tubular member 28 secured to wall I9 over opening 2I and a second tubular member, 29, secured to wall 24 and extending through opening 26 thereof into chamber 25. Tube 28 is relatively wide at its inlet end (the end secured to wall I9) and has its walls converging toward the opposite end to provide restricted throat 3I. Tube 29, connecting throat 3| has walls diverging toward closure I5, in such manner. that the Venturi tube is of constantly increasing I diameter from throat 3| to the terminal portion in chamber 25. The :terminal portion 32 of the inlet end of tube 29 is belled and contacts with a medial portion of tube 28 to define an annular" chamber 33 about throat iii, the walls of which have pluralopenings 34 into chamber 33. Secured to wall portion 32 of chamber 33 and to tube ll is a nipple 35 adapted for connection to a. suction conduit 36 which may extend to a horn, pump, windshield cleaner, or other device operable by or utilizing sub-atmospheric pressure.

' Secured to Wall 24 over opening 21 is one end of tubular member 31 which extends into chamber 25. ifhe walls of chamber 31 have perforations or apertures 38 and the end'39 thereof is adjacent to flanged plate 4|. Confined between wall 24 and plate 4! is a helical or coiled spring 42, the convolutions of which are closed or in contact when plate 4! is positioned adjacent tube end 39. The ends of the spring are respectively secured to wall 24 and theplate, so that when the latter is moved away from tube and 35, the convolutions of the spring will be separated, thereby providing an opening between chambers 23 and 25, via tube 31, perforati ns 38 and the interstices between the spring convolutions.

Closure plate 4i is carried for movement toward and from tube end 39 by a rod 43 which extends axially through the perforated tube,

through a guiding opening in wall I9, and through a bearing plug 44, the-latter being seated in an aperture in closure l2. The forward end, 46, of the rod is connected to one end of a coiled spring 41, the opposite end of the spring being attached to member 48 which is threaded to, and hence is adjustable longitudinally of, a' tube 49 which projects forwardly from the casing over the plug 43.

In operation, when the engine is operating at relatively low speeds or under light loads, so that the quantity of exhaust gases is small, the gases will pass from conduit i4, through chamber 20, through the venturi sections 23 and 29 into chamber 25, and thence to the atmosphere via discharge opening i6. Due to the small quantityof fluid passing the apparatus, the restriction provided by Venturi throat 32 will be insumcient to cause pressure to build up in chamber 20 in such excessive degree as to appreciably impede engine operation. Accordingly, since a small pressure (above atmospheric pressure) is effective in chambers 20 and 23, the closure 4! will be held seated by spring 41 and hence no fluid will pass from chambers 20 or 23 into chamber 25 except through the venturi. The term "seated has reference to closed position of convolutions of spring 42 since it is not essential that closure 4! actually contact tube 31.

Fluid passing through the Venturi tube will move at maximum velocity through the throat 3 I thereby having static pressure at this point of considerably less than atmospheric. Hence fluid will be withdrawn from annular chamber 33 through apertures 84, all in accordance with the well known Venturi" action, so that chamber 33 will be a zone of fluid undersubatmospheric pressure, and fluid will flow into same through the conduit 36 to withdraw air or other fluid from the device to which the conduit is attached.

As engine speed or load is increased, with resultant increase in the quantity of exhaust gases, excessive pressures would tend to develop in chambers 2|] and 23. However, upon the initiation of any such increase of pressure, the closure 4i will be unseated to spread the convolutions of spring 42, and thereby provide a by-passage about the Venturi tube from chamber 20 to chamber 25, via apertures 22 in wall i9, chamber 23, apertured tube 31 and the interstices between the convolutions of spring 42.

The volumetric flow capacity of the by-pass will increase as the volume of exhaust gases per unit of time increases, since the convolutions of spring 42 will open in proportion to pressure increase in chambers 20 and 23. Hence, when the engine is operating at high speed and under heavy load, a greater portion of the exhaust gases may pass through the by-passa-ge than through the Venturi tube, and, accordingly, the automatic control thus provided will tend to stabilize the flow of gas s through the venturi and the degree of suction in chamber 33.

The spring 42 will be necessarily somewhat resilient, and may be designed so as to tend to either open or close under its own resiliency. It is preferred, however, that spring 42 be subservient in its action to the spring 48, which is position d out of the path of the exhaust gases and hence will not be subject I: such excessive temperatures as might destroy its temper. By this arrangement the device will function in like manner whether the gases be cool or excessively hot. The tension of spring 48 may be varied, to vary the degree of suction or the maximum pressure in chamber 20, by adjusting the threaded spring retainer 48.

The muiiling action of the device is effected by expansion of gases in the venturi tube and by the breaking up and expansion of gases in passing the apertures 22, 38 and the interstices between the convolutions of spring 42. It will be understood that other muflling instrumcntalities may be added to the device if desired.

When the engine is operating, the flow gases entering the muflier will be of pulsating character, the number of pulsations per unit of time depending, of course, on the number of engine cylinders and engine speed. The resultant periodic increase and decrease in the volume and pressure of gases entering the mufller will cause the valve means 4H, 42 to-periodically open and close. It has been found that at high engine speeds, where the periods of pulsation are very rapid and of short duration, the inertia of the valve means will prevent complete closing at: each pulsation, and that the valve will have relatively small movement, although sufiicient. to produce an appreciable muflling action. At low engine speeds, without the Venturi means, the valve means 4!, 42 would tend to open and close with each pulse.- tion of the exhaust gases, which action is attended with more or less noise and wear upon the parts. However, as illustrated in Fig, 1, the constricted throat 3| of the venturi is of diameter approximately one fourth that of the exhaust conduit l4, and due to the sub-atmospheric pressure maintaining in the throat, it hasbeen found that the flow capacity of the venturi is approximately four times that of a straight tube of like diameter. Therefore, with the relative proportions illustrated, the Venturi tube can pass about one fourth of the maximum total volume of fluid entering from conduit I4, without unduly increasing the engine back pressure. Accordin ly, when the engine is operating at relatively low speeds, the venturi will accommodate a large portion, if not all, of the gases entering the muffler during each pulsation, and thus modify the extent of the pulsations which would otherwise impinge upon the valve means 4|, 42. In this manner the muilling effect of the device is greatly facilitated.

It will be understood, however, that the proportions indicated above should .be varied in accordance with variations in the type of engine, engine speed, and the inertia of the valve means in the mufller, so that, at such speeds of the engine as would enable the valve means 4|, 42 to substantially close between exhaust gas pulsations, the venturi will have suflicient capacity to pass substantially the entire quantity of gases exhausted from the engine.

It will be understood further that the device herein illustrated and described is merely one typical embodiment of the inventive principles 75 involved, which may be embodied in devices having other structural characteristics, without departing from the scope of this invention.

What is claimedtis:

1. In a muiiler, a casing having opposite end walls with an inlet port and an outlet port respectively, wall means separating the casing interior into an inlet chamber adjacent the inlet port and an outlet chamber adjacent the outlet port, said wall means having an opening therethrough, valve means for normally closing said opening, said valve means including a rod extending through the end wall having the'inlet port and through said opening and being movable toward the end wall having the outlet port upon opening of the valve means, resilient means disposed outside of said casing for exerting a valve closing pressure upon said rod, and means for varying such pressure of said resilient means.

2. In a mufller, a casing having inlet and outlet chambers respectively having an inlet and an outlet port, a wall between said chambers having an opening, a tube secured to the wall over said opening and having the secured end thereof communicating with the inlet chamber and having apertures in the walls thereof opening into said outlet chamber, a plate adjacent the other end of said tube mounted for movement toward and away from the tube, a helical member overlying said tube and having one end secured to said wall and the other end secured to said plate, the helical member being flexible whereby the convolutions thereof may be disposed close together or may be separated to admit of the passage of fluid therebetween, a rod extending through one end wall of said casing and having one end secured to said plate, and resilient means disposed outside of the casing exerting pressure upon the rod for urging the plate to a position wherein the convolutions of the helical member are close together.

3. In a muflier, a casing having inlet and outlet chambers respectively having an inlet and an outlet port, a wall between said chambers having an opening, a tube secured to the wall over said opening and having the secured end thereof communicating with the inlet chamber and having apertures in the walls thereof opening into said outlet chamber, a plate adjacent the other end of said tube mounted for movement toward and away from the tube, a helical member overlying said tube and having one end secured to said wall and the other end secured to said plate, the helical member being flexible whereby the convolutions thereof may be disposed close together or may be separated to admit of the passage of fluid therebetween, a rod extendpassages being a tube within the casing and having a fixed orifice of restricted area, and the other passage being defined by said tube and the casing walls and being yieldably closed by valve means, said valve means comprising a coil of wire so formed that adjacent convolutions thereof will close against each other to restrict fluid passage therebetween or open away from each other to facilitate such fluid passage, resilient means for urging said adjacent convolutions to close against each other, and fluid pressure actuated means for urging the convolutions to open away from each other.

5. In a muflier, a casing having an inlet opening adjacent one end thereof and an outlet opening adjacent the opposite end thereof, a periorated wall adjacent the inlet end and a second wall adjacent the outlet end, a v nturi tube with a suction take-off at the restricted portion thereof, said tube extending within said casing between said walls and having its inlet end opening into the chamber between the first mentioned wall and the casing end having the inlet opening and in alignment with the latter, and said tube discharging into the chamber between said ERWIN C. HORTON. 

